Grating sound at or around 1000 rmp

[Jerry84]

My engine, w11 sr20det, is making a grating sound at or around 1000 rpm. What could be the possible causes? I've noticed that this is more prevalent when the air condition is on. I visited the air condition technician and he confirmed that the compressor, bearing etc is good.

However it seems that the front engine seal has a small oil leak and need to be changed.

Could this be the cause?

[Jerry84]

Note that outside of the range, whether it's under or over the 1000 rpm range, you are not hearing it.